1. Field of the Invention
The present invention relates to an image heating device, effecting heating with an eddy current generated by electromagnetic induction, and more particularly to an image heating device for fixing an unfixed image in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus.
2. Related Background Art
In the image heating device represented by a thermal fixing device, there has widely been used the contact heating method, such as utilizing a heat roller. In particular, for fixing a color image having four toner layers at maximum, the toner image is heated by a halogen heater through a metal core and an elastic rubber layer of the fixing roller.
On the other hand, the Japanese Patent Publication No. 5-9027 proposes to utilize Joule heat generated by an eddy current induced in the fixing roller by a magnetic flux.
Utilization of such eddy current allows to bring the position of heat generation closer to the toner image, thereby leading to an improved efficiency of the energy consumption, in comparison with that of the heat roller utilizing the halogen lamp.
However, in the device disclosed in the Japanese Patent Publication No. 5-9027, though the magnetizing core is positioned relatively close to the cylindrical member, the magnetizing coil which generates the magnetic flux is still distant from the cylindrical member, so that the heat efficiency is not so high.
An object of the present invention is to provide an image heating device capable of improving the heat efficiency in heat generation in a movable member by a magnetizing coil.
Another object of the present invention is to provide an image heating device in which a magnetizing coil provided continuously over the entire width of the movable member, is provided along the movable member without at least partially along a core material.
Still another object of the present invention is to provide an image heating device in which a magnetizing coil provided continuously over the entire width of the movable member, is provided so that a substantially entire portion of an upstream side of the nip of the magnetizing coil is along the movable member.
Still other objects of the present invention, and the features thereof, will become fully apparent from the following description.